Compositions containing quaternary ammonium salts or imidazolinium compounds having at least one long chain hydrocarbyl group are commonly used to provide fabric softening benefits when used in a laundry rinse operation. Numerous patents have been issued for these types of compounds and compositions.
More recently, however, in view of concerns for the environmental safety (e.g., biodegradability) of the quaternary compound softeners, as well as limits in the amounts of these cationic compounds which can be stably incorporated into the more convenient to use liquid formulations, there have been many proposals for partial or total replacements of the conventional "quat" fabric softeners which are exemplified by dimethyl distearyl (or ditallow) ammonium chloride and various imidazolinium compounds.
For instance in GB 2,032,479A, corresponding to EP 038862, to D. Fontanesi (assigned to Albright & Wilson Ltd.) water dispersible unquaternized hydroxyalkyl diamidoamine compounds of formula EQU RNH((CH.sub.2).sub.n NR).sub.m R
wherein an average of from 20% to 80% of the R groups are C.sub.12 to C.sub.22 acyl, at least 20% of the R groups are --CH.sub.2 CH.sub.2 OH or --CH.sub.2 CHOHCH.sub.3 or mixtures of these groups, and any other R group is hydrogen, n is 2 or 3 and m is an integer of from 2 to 5, are provided as mobile pastes in the presence of lower alkanol solvents. This is stated to be in contrast to partially neutralized unquaternized diamidoamines which, while providing highly effective fabric softening properties, are too viscous even when diluted in the lower alkanol solvents for convenient handling.
U.S. Pat. No. 5,154,838 (corresponding to EP 0459211A2) to Yomamura, et al. (assigned to Kao Corp.) discloses an aqueous liquid softener composition based on an amidoamine compound which is the condensation reaction product of a di- or tri-amine of formula (I): EQU R.sup.1 NH(C.sub.m H.sub.2m NH).sub.n H (I)
with a fatty acid of formula (II): ##STR1## wherein R.sup.1 represents a straight or branched chain, saturated or unsaturated hydrocarbon group having 8 to 24 carbon atoms, R.sup.2 represents a straight or branched, saturated or unsaturated hydrocarbon group having 7 to 23 carbon atoms, m represents 2 or 3, and n is 1 or 2. These compounds, which are neither hydroxylated or ethoxylated, are noted to have high dispersibility in rinse water, especially when the amidoamine compound is used in the form of its neutral salt.
U.S. Pat. No. 5,108,628 to Uphues, et al. (Henkel) discloses certain aliphatic carboxylic acid amidoamines which are obtained by reaction of polyamines (e.g., diethylentriamine, aminoethyl ethanolamine) with carboxylic acid mixtures containing ether carboxylic acids (R--O--(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 COOH, R=C.sub.8-18 alkyl, C.sub.8-18 alkenyl or CH.sub.2 --COOH, n=2 to 20, in combination with aliphatic C.sub.8-22 monocarboxylic acids and/or amide-forming aliphatic C.sub.8-22 monocarboxylic acid derivatives) as fabric softeners stable in the presence of electrolytes.
In U.S. Pat. No. 5,133,885 to L. Contor, et al. (corresponding to EP 0423894, both assigned to Colgate-Palmolive Company, the assignee of the present invention) fabric softening compositions are described which are aqueous dispersions of a fatty acid ester quat of formula: ##STR2## where one or two R groups represent an aliphatic ester residue of from 12 to 30 carbon atoms of formula C.sub.n H.sub.2n OCOR.sub.4, and the remaining R groups represent lower aliphatic, aryl or hydroxyalkyl groups, X.sup.- is an anion and "a" represents the ionic valence of the anion, and a fatty acid amidoamine softener of formula: ##STR3## where R.sup.1 is a C.sub.12 to C.sub.30 alkyl or alkenyl group, R.sup.2 represents R.sup.1, R.sup.1 CONH(CH.sub.2).sub.m or CH.sub.2 CH.sub.2 OH; R.sup.3 represents hydrogen, methyl, or (CH.sub.2 CH.sub.2 O).sub.p H, m is a number of 1 to 5 and p is a number of 1 to 5, at a weight ratio of ester quat to amidoamine of from 10:1 to 1:10. This patent discloses total amounts of esterquat and amidoamine ranging from 3% to 60% by weight, however, compositions containing at most 8% by weight of active softeners are disclosed.
U.S. Pat. No. 5,180,508 to Birkhan, et al. (corresponding to EP 0413249, assigned to Witco Surfactants GmbH) discloses aqueous fabric softener rinsing agents based upon a mixture of quaternary salt compounds: a first component (a) of formula (I) ##STR4## wherein, each R is independently hydrogen or lower alkyl;
each R.sup.1 is hydrogen or an alkylcarbonyl group containing 15-23 carbon atoms, provided that at least one of R.sup.1 is an alkylcarbonyl group; PA1 each R.sup.3 is an alkyl group containing 1-4 carbon atoms which is unsubstituted or substituted with 1, 2, or 3 hydroxy groups; PA1 each R.sup.2 is an alkyl group containing 1-4 carbon atoms which may be unsubstituted or substituted with 1, 2, or 3 hydroxy groups, or is a group of the formula: ##STR5## R.sup.13 is an alkyl group containing 8-22 carbon atoms; R.sup.12 is an alkyl group containing 1-4 carbon atoms which is unsubstituted or substituted with 1, 2, or 3 hydroxy groups; PA1 R.sup.11 is hydrogen or lower alkyl; PA1 R.sup.10 is hydrogen or alkylcarbonyl group containing 14-22 carbon atoms; PA1 A is an anion of a quaternizing agent; PA1 X and Y are independently hydrogen or lower alkyl (but not both alkyl); PA1 R.sup.7 is an alkylcarbonyl group containing 4-22 carbon atoms or H; PA1 R.sup.9 is an alkyl group containing 14-22 carbon atoms; PA1 Z.sub.1 is a water-soluble monobasic or polybasic anion; PA1 d and d.sub.1 are independently 0-6; q is 0 or 1; f.sub.1 is 1, 2 or 3; p is 1-3; and p+q&gt;2. PA1 (A') an inorganic or organic acid salt of bis(hydrogenated tallow amidoethyl) hydroxyethyl amine, PA1 (B') an inorganic or organic acid salt of bis(non-hydrogenated tallow amidoethyl) hydroxyethyl amine, with the total amount of (A') and (B') being from about 2% to about 50% by weight of the composition, and the ratio by weight of (A') to (B') being in the range of from about 10:1 to about 1.5:1, and an aqueous solvent. PA1 (A) a softening effective amount of an inorganic or organic acid salt of a finely divided fatty amido tertiary amine compound of formula (I): ##STR9## wherein R.sub.1 and R.sub.2, independently, represent C.sub.12 to C.sub.20 alkyl or alkenyl; R.sub.3 represents (CH.sub.2 CH.sub.2 O).sub.p H, CH.sub.3 or H; T represents O or NH; n and m are each, independently, a number of 1 to 5; and p is a number of from 1 to 10; PA1 (B) a viscosity controlling and softening improving effective amount of a defined cyclic imidazolinium compound; and PA1 (C) an aqueous solvent including an anti-gelling effective amount of electrolyte. Compositions containing up to 25 wt. % of active ingredients (A) and (B) are exemplified, with amounts of (A) and (B) up to 60% being disclosed. PA1 (A) is (i) an inorganic or organic acid salt of an amidoamine compound of formula (I): ##STR10## wherein R.sub.1 and R.sub.2 represent C.sub.11 to C.sub.29 aliphatic hydrocarbon groups, PA1 R.sub.3 represents ##STR11## or H wherein p is a number from 1 to 10 and R.sub.8 is CH.sub.3, CH.sub.2 CH.sub.3 or H, and PA1 n and m are each, independently, a number from 1 to 5; or (ii) an amidoquaternary ammonium compound of formula (II): ##STR12## wherein R.sub.4 represents ##STR13## or CH.sub.3 ; R.sub.1, R.sub.2, R.sub.8, n and m are as defined above, and X is an inorganic or an organic anion of valence a; and PA1 (B) is a biodegradable diacid polymeric fatty ester quaternary ammonium compound of formula (III): ##STR14## wherein R.sub.5 represents a C.sub.1 to C.sub.18 aliphatic hydrocarbon group, and each R.sub.6 independently represents a C.sub.11 to C.sub.29 aliphatic hydrocarbon group, PA1 R.sub.7 represents a C.sub.1 to C.sub.4 alkyl group, PA1 n, m and p are each, independently, a number from 1 to 4, PA1 q is a number from 1 to 3, and PA1 X is an inorganic or organic anion of valence a; and PA1 (C) an aqueous solvent including an anti-gelling effective amount of electrolyte. PA1 n, m, and p, each, independently, represent a number from 1 to 4, and q represents a number from 1 to 3. PA1 X represents a counter ion of valence a such as Cl.sup.-, Br.sup.-, I.sup.-, CH.sub.3 OSO.sub.3.sup.-, CH.sub.3 CH.sub.2 OSO.sub.3.sup.-, (CH.sub.3 O).sub.2 PO.sub.2 and the like.
n is 0 or 1; PA2 x and y are independently 0 or 1 with the proviso that (x+y)+(3-n)=4; and PA2 m is 1 or 2; and g is 1, 2 or 3, such that (m/g)(g)=m, and
a second component (b) which is a quaternary salt of an imidazolinium compound (III), an amidoamine compound (IV), an ammonium compound (V), or diimidazolinium compound (VI). The amidoamine compound has the formula: ##STR6## wherein R.sup.6.sub.1 is CHX--CHY--O;
The mixture of the soft-rinsing agent (a) and (b) constitutes from 10 to 25% by weight of the composition at ratios of (a):(b) of from 1:9 to 9:1. The alkyl groups in R.sup.7 and R.sup.9 are preferably completely saturated. Viscosity control agents, including electrolyte salts, e.g., calcium chloride, may be included.
U.S. Pat. No. 4,724,089 to Konig, et al. discloses aqueous dispersions of certain amines, including reaction products of higher fatty acids with a polyamine (e.g., ##STR7## where R.sub.1 =acyclic aliphatic C.sub.15 -C.sub.21 hydrocarbon; R.sub.2 and R.sub.3 =divalent C.sub.1 -C.sub.3 alkylene groups) with a dispersing aid (e.g., HCl) and, optionally, quaternary ammonium salt (e.g., diamido (alkoxylated) quaternary ammonium salts). Relatively small amounts of electrolyte, e.g., CaCl.sub.2, can be added to adjust viscosity.
EP 0295,386 to Ruback, et al. discloses a free-flowing softening washing rinse concentrate containing (a) from 18 to 50 weight percent of a mixture of at least two quaternary ammonium salts: (A) 10-90 wt. % of triethanol-amine ester quaternary ammonium compound, and (B) 90 to 10 wt. % of another quaternary compound including quaternized amidoamine (or equivalent esteramine or thioamine) and (b) water and optional conventional additives.
While these and many other proposals are known for improved fabric softening compositions, nevertheless, still further improvements are desired.
One such proposal is described by Schramm, et al. in U.S. Pat. No. 5,476,598. According to this proposal stable, aqueous, pourable and water dispersible, fabric softener compositions are provided which include (A) a fabric softening effective amount of an inorganic or organic acid salt of a finely divided softening compound of formula (I): ##STR8## wherein R.sub.1 and R.sub.2, independently, represent C.sub.12 to C.sub.20 alkyl or alkenyl; R.sub.3 represents (CH.sub.2 CH.sub.2 O).sub.p H, CH.sub.3 or H; n and m are each a number of from 1 to 5; and p is a number of from 1 to 10; (B) a stabilizing amount of a defined emulsifier-dispersing agent; and (C) an aqueous solvent. The compositions are provided as ready-to-use products or as concentrates to be used at reduced levels or which may be diluted with water prior to use at the same or similar levels as the ready-to-use products. In the ready-to-use composition the total amount of amidoamine softener (A) and stabilizing dispersant (B) is disclosed to fall in the range of from about 2 to 8% by weight. In the concentrated form the total amount of (A) and (B) is generally in the range of from about 12 to 60% and may be diluted at ratios of water:concentrate as high as about 4:1 to even 8:1 or 9:1, and still provide acceptable softening performance, equivalent or better than that achieved using conventional quaternary cationic surfactant softeners, such as dimethyl distearyl ammonium chloride (DMDSAC).
An alternative embodiment of the Schramm, Jr., et al. fabric softener aqueous liquid compositions which is adaptable for use in the rinse cycle of a laundering process and which is described as stable, pourable, and dispersible in water, includes the following ingredients:
The compositions disclosed in the aforesaid U.S. Pat. No. 5,476,598 to Schramm et al. provide highly effective stable and pourable liquid fabric softener compositions; nevertheless, in practice it is found that with concentrations of the amidoamine fabric softening compound (e.g. Varisoft 510) in excess of 11 weight percent in the presence of certain emulsifiers, such as hydrogenated tallow, the product viscosity becomes excessively high, even in the presence of electrolytes (e.g. CaCl.sub.2) or solvents (e.g. propanol). While higher total concentrations of the amidoamine were achieved using the soft tallow product Varisoft 512 or mixtures of Varisoft 512 and hard tallow product, Varisoft 510, the softening performance of the Varisoft 512 containing compositions, was not sufficiently improved.
The prior art has focused attention on ways to increase the concentration in the liquid fabric softening composition of the amidoamine softener compound Varisoft 510 in view of its very good environmental attributes and favorable acute toxicity data as well as its strong softening performance. However, as noted above, at high concentrations the viscosity increases substantially until gelation occurs.
It was recently discovered that the incorporation of cyclic imidazolinium compounds can increase the concentratability of fatty amido tertiary amine softeners and also significantly improve the softening efficacy of Varisoft 510. This discovery is described in greater detail in U.S. Pat. No. 5,468,398 to Farooq et al. According to this patent a stable, pourable, water dispersible aqueous liquid fabric softener composition includes:
In an effort to provide concentrated liquid fabric softening compositions containing more than 25%, by weight, of a softening system based on amido amine and a diesterquaternary compound, there is described in U.S. Pat. No. 5,501,806 to Farooq et al. a concentrated softening composition characterized by hydrocarbon groups in the defined softening compounds which have a specified degree of unsaturation to create a stable and efficacious softening composition. The two active softening compounds in the compositions are stated to comprise from about 25% to about 50%, by weight, of the softening composition.
Notwithstanding the various improvements described in the patent literature in formulating liquid fabric softening compositions, there remains a need for alternatives to current commercial rinse cycle fabric softening compositions which offer equivalent or enhanced softening performance concomitant with improved biodegradability and lower ecotoxicity relative to present-day commercial softening compositions.